Sero-epidemiological survey of Crimean-Congo hemorrhagic fever virus in Tunisia

Abstract

Crimean-Congo hemorrhagic fever (CCHF) is a tick-borne disease associated with a high case fatality rate and transmitted mainly by Hyalomma marginatum. The geographical distribution of H. marginatum covers most of the Western Mediterranean basin. We aimed to investigate whether CCHF virus (CCHFv) is circulating in Tunisia. Samples from unexplained acute febrile patients (n = 181) and a high risk group of humans, mainly slaughter workers (n = 38), were collected in the summer of 2014 and analyzed for exposure to CCHFv using serological tests and real-time RT-PCR. Ticks were collected from Northern and Southern Tunisia during May–June 2014 and examined for the presence of CCHFv by real-time RT-PCR. Of the 181 febrile patients, 5 showed only high titers of IgM suggesting a recent exposure to CCHFv. Among 38 slaughter workers, 2 had IgG anti-CCHFv responses yielding a seroprevalence of 5.2%. No CCHFv was detected in ticks and sera. Our results provide evidence of human exposure to CCHFv in Tunisia.

Sensitive and specific detection of Crimean-Congo Hemorrhagic Fever Virus (CCHFV)—Specific IgM and IgG antibodies in human sera using recombinant CCHFV nucleoprotein as antigen in μ-capture and IgG immune complex (IC) ELISA tests

“…Results obtained with the BLACKBOX IgM/IgG ELISAs were compared with the respective in-house serological gold standard (CCHFV IgM/IgG IIFT) and commercial ELISA tests (VectoCrimean-CHF-IgM/IgG, Vector-Best, Russia) that have been extensively used for seroprevalence studies in various countries (e.g. Turkey [ 39 – 42 ], Greece [ 43 – 47 ], Bulgaria [ 48 ], Afghanistan [ 49 ], Kosovo [ 36 ], Tunisia [ 50 ], Ghana [ 51 ]) and for the diagnosis of acute cases [ 52 , 53 ]. Recently, a collaborative evaluation of both the VectoCrimean-CHF-IgG and the VectoCrimean-CHF-IgM test in five reference laboratories revealed a sensitivity of 87.8% (range 75.2%–95.3%) for the VectoCrimean-CHF-IgM test and a sensitivity of 80.4% (range 66.9%–90.2%) for the VectoCrimean-CHF-IgG test when compared with the respective in-house reference serological tests [ 3 ].…”

Current status of Crimean-Congo haemorrhagic fever in the World Health Organization Eastern Mediterranean Region: issues, challenges, and future directions

“…14 In a survey in Tunisia conducted in 2014, of the 181 febrile patients, only five showed high IgM titres suggesting recent exposure to CCHFV. 48 Among 38 slaughterhouse workers, two had IgG anti-CCHFV responses, yielding a seroprevalence of 5.2%. No CCHFV was detected in ticks or sera.…”

“…No CCHFV was detected in ticks or sera. 48 In Egypt, 49,50 Syria, and Somalia, 40 CCHFV-specific IgG has been confirmed or detected in animals; however, there has been no evidence of viral infection in humans. In Morocco, CCHFV nucleic acid has been detected in ticks removed from migratory birds.…”

Isolation, Characterization, and Phylogenetic Analysis of Two New Crimean-Congo Hemorrhagic Fever Virus Strains from the Northern Region of Xinjiang Province, China

“…Thereafter, outbreaks and further cases of CCHF were reported in wide areas in countries in Africa (Uganda, South Africa, Sudan, and Mauritania), the Middle East (Iraq, United Arab Emirates, Iran, Oman, and Saudi Arabia), Europe (Bulgaria, Kosovo, Turkey, and Albania), and Asia (China, Pakistan, Afghanistan, and India) (Ergonul 2006). Serological evidence for CCHFV further suggested the potential prevalence of this virus in a wider geographic distribution including Malaysian, Nigeria, Tunisia, Sub-Saharan Africa, Iberian Peninsula (Bukbuk et al 2014(Bukbuk et al , 2016Mohd Shukri et al 2015;Muianga et al 2017;Palomar et al 2017;Wasfi et al 2016). Hence, CCHFV may be more widely distributed worldwide than is currently known.…”